Flat roof replacement on 1960s block of 15 flats.

Twbma6LC

As Leaseholders we have recently acquired the Right to Manage our block of 15 flats. We are faced with some very large costs due to lack of maintenance and no sinking fund despite high service charges for many years.  The flat roof needs replacement and one proposal is encapsulation by a Polyurethane membrane. This process seems to be a cost effective and safe solution used mainly for industrial and commercial buildings. It has been suggested as a cost effective solution at over 50% cheaper than traditional methods. Has anyone experience of this in a residential context?  If this is so good why is it not used more widely? Are there any specific disadvantages we should be aware of?  Our managing agent had not heard of this being used on residential blocks.  Any information gratefully received. 

Lorian

No experience of this but Resitrix re-enforced epdm (and suitable Insulation)/vapour barrier maybe another alternative to consider.

ThisIsWeird

Unless it's falling apart, a deteriorating flat roof can be prolonged for years with a fibre-containing roofing product such a Cromopol (and others).
This should allow you time to build up funds. Bear in mind that a full recovering may involve the compulsory addition of insulation, if it doesn't already have this.
Sorry, I haven't heard of the system you mentioned. Is it like EPDM? I guess that should work, and be very long lasting, but the existing roof would have to be of an adequately sound standard. There's also GRP alternatives such as Flexitec 2000 - seemingly requires only a single mat layer due to the quality and flexibility of the resin coating.
What's the current roof finish? And how bad is it?

Twbma6LC

Thanks for feedback. It’s a 60s block with the original roof which is falling apart! There have been several repairs and we now have water literally pouring into three flats through the old airing cupboards where flue pipes ran. Affected flats are on each floor ( 3 in total) with the middle level recently baling out 60 litres in a 24 hr period  and the flat largely uninhabitable because of the extent of the damage and smell. We are having yet another emergency repair (previous ones being done by the then management company and not guaranteed) but looking at replacement.  

The deck is unscreeded Woodwool slabs with membrane 1 mod bitumen 2 ply hot applied and another membrane mod bitumen 1 ply torch applied. 

Question also raised is whether using encapsulation may mean that flats may not be  mortgageable and therefore impact resale. If anyone can answer this one much appreciated. 

ThisIsWeird

I don't know enough about this, but there seems no point to me in 'encapsulating' a rotten, fragile roof.

I would suggest that a full recover is needed, and this will include an enhanced level of insulation, to everyone's benefit. Save up for this. Meanwhile, use whatever is required - felt, Cromopol, part-encapsulation, whatever, to seal the sources of these leaks and prevent further damage. How many roofers have been out to have a look at a 'patching' job?

Twbma6LC

There have been 3 repairs to date, arranged by previous Management Company none of which are guaranteed. Problem has become progressively worse. Now instructed one of companies that have quoted for job to do yet another emergency repair. 

Costs for encapsulation approx. £45,000, traditional felt / bitumen approximately £90,000 and four contractors quoting against Garland system specification ranging from £114,000 to £175,000. All a bit of a nightmare! 

ThisIsWeird

Twbma6LC said:

There have been 3 repairs to date, arranged by previous Management Company none of which are guaranteed. Problem has become progressively worse. Now instructed one of companies that have quoted for job to do yet another emergency repair. 

Costs for encapsulation approx. £45,000, traditional felt / bitumen approximately £90,000 and four contractors quoting against Garland system specification ranging from £114,000 to £175,000. All a bit of a nightmare! 

The situation is getting worse - in what way? Are fresh leaks appearing, or are the old ones reappearing?

How much do these patches/repairs cost each time?

It would help to know what, exactly, is going on with your roof, ideally with photos.

And it would be useful to know what the 'Garland system' repair would include.

But, if we are talking of a full roof repair and recover - ie a 'permanent' fix - for ~£115k, then it doesn't make sense to me to 'encapsulate' for £45k - unless that is also considered pretty much permanent, or at least an expected 20-year life.

I don't know enough about roofing systems to comment much further, I'm afraid. But, if 'encapsulation' does mean that the whole roof is covered with a bonded-down layer of EPDM, then that is an established and reputable roofing system. It would need to come with a warranty, tho'.

Do you have the 'specs' for each solution? Encaps and Garland?

Duple

Twbma6LC said:

There have been 3 repairs to date, arranged by previous Management Company none of which are guaranteed. Problem has become progressively worse. Now instructed one of companies that have quoted for job to do yet another emergency repair. 

Costs for encapsulation approx. £45,000, traditional felt / bitumen approximately £90,000 and four contractors quoting against Garland system specification ranging from £114,000 to £175,000. All a bit of a nightmare! 

Garland is very expansive. Get quotations using other system like Icopal, Bauder, IKO...etc. We had Icopal in our building that came with a 25 years insurance backed warranty. Manufacture visited several stages to inspect contractor's work. Having an good installation is very important. 

Cloth_of_Gold

Duple said:

Twbma6LC said:

There have been 3 repairs to date, arranged by previous Management Company none of which are guaranteed. Problem has become progressively worse. Now instructed one of companies that have quoted for job to do yet another emergency repair. 

Costs for encapsulation approx. £45,000, traditional felt / bitumen approximately £90,000 and four contractors quoting against Garland system specification ranging from £114,000 to £175,000. All a bit of a nightmare! 

Garland is very expansive. Get quotations using other system like Icopal, Bauder, IKO...etc. We had Icopal in our building that came with a 25 years insurance backed warranty. Manufacture visited several stages to inspect contractor's work. Having an good installation is very important. 

It looks impressive but it also looks as if it 's manly geared towards commercial buildings and pretty expensive. How large is your building and how much did it cost, if you don't mind sharing that?

Twbma6LC

Thanks. 

Last patch repair has worked so gained a bit of time but roof needs replacement. 

Block is three storeys high with total 15 flats. Roof area approximately 95 square metres. Quote due on ‘encapsulation’ in a couple of weeks. 

Still struggling to understand why spray coatings aren’t used widely in private housing by developers if they’re so cost effective.